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Home My WebLink About20066_Parkwood_Decision Memo_20170418DECISION MEMORANDUM DATE: April 18, 2017 FROM: Jordan Thompson TO: BF Assessment File RE: Parkwood Station 1702, 1706, and 1720 N. Brevard St.; 1721 N. Caldwell St.; 414 and 418 E. 21st St.; and 427 E. 20th St. Charlotte, Mecklenburg County BF # 20066-16-060 Based on the following information, it has been determined that the above referenced site, whose intended use is for no uses other than high density residential, can be made suitable for such uses. Introduction: The Brownfields Property is comprised of four parcels (Mecklenburg County parcel #s 08107803, 08304101, 08304103, and 08304106) totaling 3.553 acres located north of N. Caldwell St., east of Parkwood Ave., south of N. Brevard St., and west of E. 21st St. The Brownfields Property is developed with three industrial buildings and a residence. The industrial buildings were recently vacated by Industrial Sign and Graphics, a sign manufacturing company, and the residence is being vacated by residential tenants. Groundwater is impacted with VOCs above 2L Standards at the property due to migration from an upgradient source to the northwest of the Brownfields Property, and soil is impacted with arsenic and hexavalent chromium above residential soil screening criteria, that appears to be naturally occurring. The surrounding area is residential, commercial, and railroad tracks followed by a railroad depot. Redevelopment Plans: The Brownfields Property is proposed to be redeveloped for high density residential, retail, and commercial uses following demolition of the current buildings and site grading activities. Site History: The Brownfields Property totals 3.553 acres and is developed with three industrial buildings and a residence. The property was initially developed with residences prior to 1929 and the residences were demolished in stages between 1929 and 1973, with the exception of the remaining residence. Portions of the current industrial buildings were constructed between 1929 and 1993 that were built in sections and as additions to existing buildings. Historical operations on the Brownfields Property included a wiper & waste cloth manufacturing facility (with associated laundry and machine shop), the Charlotte Workshop for the Blind, Carolina Tool and Die, and Keeter Dixon Pearre, a textile recycling facility, from the 1950s through the mid-1990s. The Brownfields Property was most recently occupied by Industrial Sign and Graphics from the mid-1990s until late 2016. The remaining residence has been occupied by residential tenants since initial construction. Potential Receptors: Potential receptors are: construction workers, on-site workers, future residences, visitors, and trespassers. A Brownfields receptor survey was completed in December 2016 that indicated that properties immediately adjacent to the property were serviced by municipal water. Contaminated Media: DEQ has evaluated data collected from the following media at the subject property: soil, groundwater, and soil gas. DEQ relies on the following data to base its conclusions regarding the subject property and its suitability for its intended reuse. A Phase II ESA was completed for the Brownfields Property in August 2016 that identified soil impacts of metals above DEQ IHSB residential screening criteria and groundwater impacts of VOCs above DEQ 2L Standards. Additional assessment completed in November 2016 identified similar concentrations of metals and identified PAHs above residential screening criteria. Soil The most recent soil assessment was conducted on November 29, 2016 and is detailed in a Report of Additional Assessment completed by ESP Associates. Five soil borings were installed and 11 soil samples collected from anticipated cut depths for site grading and potential source areas not previously investigated. Additionally, four surficial (0-2 ft bgs) soil borings were installed and one composite sample collected from the vicinity of the residence for analysis of total lead. The soil samples were analyzed for VOCs, SVOCs, and RCRA metals. Analytical results indicated soil impacts of arsenic above DEQ IHSB residential screening criteria throughout the Brownfields Property. One boring had impacts of three SVOC compounds above residential screening criteria in the southwestern portion of the Brownfields Property. During a previous soil assessment in August 2016, soil impacts of arsenic were identified at similar concentrations throughout the Brownfields Property. The arsenic impacts on the Brownfields Property are considered to be naturally occurring based on the consistent concentrations identified across the site at levels typically observed in many native soils and that there appear to be no historical industrial processes at this site from which arsenic is an expected contaminant. Additionally, hexavalent chromium was identified in two soil samples at 13.5-15 ft bgs above IHSB residential standards. The location of the identified hexavalent chromium impacts is intended to be covered with at least 2 additional feet of fill, bringing the depth to 15.5-17 ft bgs. Based on the identified depth of hexavalent chromium impacts, the placement of fill on top of the impacts, and the requirement of final grade sampling on “open” areas of the property, the potential for exposure from metals and PAHs on the Brownfields Property has been minimized. The table below demonstrates the hazard quotient of soils on-site based on the highest concentrations identified. The residential hazard quotient is 0.35, well below the limit of 1.0. Refer to the attached Phase II ESA dated August 2016, Report of Additional Assessment dated December 2016, and Exhibit 2. Groundwater The most recent groundwater assessment was conducted in July 2016 and detailed in a Phase II ESA completed by ESP Associates. Groundwater impacts of tetrachloroethylene, total chromium, and bis(2-ethylhexyl)phthalate were identified above 2L Standards in the western portion of the Brownfields Property that is migrating from an upgradient, offsite, source. The table below demonstrates that the highest concentrations detected during the July 2016 sampling event were above the VISL Calculator Hazard Index of 1. Therefore, soil gas samples were collected in the vicinity of identified groundwater impacts. Refer to the attached Phase II ESA and Exhibit 2 for the detected concentrations. Surface Water Surface water is not located on the Brownfields Property. The nearest water body is Little Sugar Creek located approximately 600 ft southeast of the Site. Soil Vapor Four soil gas sample points were installed in the western portion of the Site within the anticipated footprint of future site buildings in December 2016 and detailed in the Report of Additional Assessment completed by ESP Associates. Tetrachloroethylene was detected at one sample location above the DEQ Residential SGSL. The table below demonstrates the highest concentrations detected were below the VISL Calculator Hazard Index of 1. Based on the detected concentrations of VOCs and planned use of an active mitigation system beneath all Site buildings, the identified concentrations are acceptable for property redevelopment of high density residential uses with the planned mitigation measures. Sub-Slab Vapor No sub-slab testing was completed. Indoor Air Because an active mitigation system will be installed, no indoor air testing was completed. Confirmation indoor air samples will be required as part of a vapor mitigation plan. Risk Calculations Risk Calculations were performed using Excel worksheets provided by Sandy Mort, NCDEQ Brownfields Toxicologist. The Brownfields Site was evaluated as a whole for soil and groundwater impacts and soil vapor points were collected in the western portion of the Site based on the impacts of groundwater above 2L Standards identified during the Phase II ESA assessment. The risk calculations indicated the following based on available data, including the following media: groundwater, residual soil (based on confirmatory soil data), soil gas, indoor air, and fill soil samples: Medium Site Area Residential Non-Residential LICR HI LICR HI Groundwater All 9.0 x 10-5 1.47 2.1 x 10-5 0.350 Soil Vapor Western portion of the Site 1.0 x 10-5 0.762 7.9 x 10-7 0.0605 Residual Soil Max All 3.1 x 10-5 0.35 4.35 x 10-6 0.239 Red shading LICR> 1E-04 or HI> 1. LICR = Lifetime Incremental Cancer Risk HI = Hazard Index Based on the planned reuse of the property for a high density residential property and the planned installation of active mitigation systems for all Site buildings, groundwater, soil, and indoor air hazard quotients are acceptable. Final grade sampling will be required during any soil disturbance as part of an EMP and confirmation indoor air samples will be required as part of a vapor mitigation plan to ensure lack of potential exposure. Required Land Use Restrictions: Based on the site-specific data provided to the Brownfield program, the site reuse is suitable as long as the agreed upon land use restrictions in the BFA are abided by. - No daycares - No groundwater use - no soil disturbance - Final grade sampling of soil - No soil brought onto or removed from property without DEQ approval - No enclosed building constructed without DEQ approval of vapor intrusion assessment/mitigation. - No surface water use other than stormwater - EMP required for redevelopment - DEQ cannot be denied access - Deed conveyance of BFA - Known contaminants on the property may not be kept or stored on-site - MW replacement if damaged or destroyed - LURU submittal